1 /*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91
33 * $FreeBSD: releng/12.0/sys/i386/i386/sigtramp.s 332489 2018-04-13 20:30:49Z kib $
34 *
35 * originally from: locore.s, by William F. Jolitz
36 *
37 * Substantially rewritten by David Greenman, Rod Grimes,
38 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
39 * and many others.
40 */
41
42 #include <sys/syscall.h>
43 #include <machine/asmacros.h>
44 #include <machine/psl.h>
45
46 #include "assym.inc"
47
48 /*
49 * Signal trampoline, copied to top of user stack
50 */
51 NON_GPROF_ENTRY(sigcode)
52 calll *SIGF_HANDLER(%esp)
53 leal SIGF_UC(%esp),%eax /* get ucontext */
54 pushl %eax
55 testl $PSL_VM,UC_EFLAGS(%eax)
56 jne 1f
57 mov UC_GS(%eax),%gs /* restore %gs */
58 1:
59 movl $SYS_sigreturn,%eax
60 pushl %eax /* junk to fake return addr. */
61 int $0x80 /* enter kernel with args */
62 /* on stack */
63 1:
64 jmp 1b
65
66 #ifdef COMPAT_FREEBSD4
67 ALIGN_TEXT
68 freebsd4_sigcode:
69 calll *SIGF_HANDLER(%esp)
70 leal SIGF_UC4(%esp),%eax /* get ucontext */
71 pushl %eax
72 testl $PSL_VM,UC4_EFLAGS(%eax)
73 jne 1f
74 mov UC4_GS(%eax),%gs /* restore %gs */
75 1:
76 movl $344,%eax /* 4.x SYS_sigreturn */
77 pushl %eax /* junk to fake return addr. */
78 int $0x80 /* enter kernel with args */
79 /* on stack */
80 1:
81 jmp 1b
82 #endif
83
84 #ifdef COMPAT_43
85 ALIGN_TEXT
86 osigcode:
87 call *SIGF_HANDLER(%esp) /* call signal handler */
88 lea SIGF_SC(%esp),%eax /* get sigcontext */
89 pushl %eax
90 testl $PSL_VM,SC_PS(%eax)
91 jne 9f
92 mov SC_GS(%eax),%gs /* restore %gs */
93 9:
94 movl $103,%eax /* 3.x SYS_sigreturn */
95 pushl %eax /* junk to fake return addr. */
96 int $0x80 /* enter kernel with args */
97 0: jmp 0b
98
99 /*
100 * Our lcall $7,$0 handler remains in user mode (ring 3), since lcalls
101 * don't change the interrupt mask, so if this one went directly to the
102 * kernel then there would be a window with interrupts enabled in kernel
103 * mode, and all interrupt handlers would have to be almost as complicated
104 * as the NMI handler to support this.
105 *
106 * Instead, convert the lcall to an int0x80 call. The kernel does most
107 * of the conversion by popping the lcall return values off the user
108 * stack and returning to them instead of to here, except when the
109 * conversion itself fails. Adjusting the stack here is impossible for
110 * vfork() and harder for other syscalls.
111 */
112 ALIGN_TEXT
113 lcall_tramp:
114 int $0x80
115 1: jmp 1b
116
117 #endif /* COMPAT_43 */
118
119 ALIGN_TEXT
120 esigcode:
121
122 .data
123 .globl szsigcode
124 szsigcode:
125 .long esigcode-sigcode
126 #ifdef COMPAT_FREEBSD4
127 .globl szfreebsd4_sigcode
128 szfreebsd4_sigcode:
129 .long esigcode-freebsd4_sigcode
130 #endif
131 #ifdef COMPAT_43
132 .globl szosigcode
133 szosigcode:
134 .long esigcode-osigcode
135 .globl sz_lcall_tramp
136 sz_lcall_tramp:
137 .long esigcode-lcall_tramp
138 #endif
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